Characterization of the high-affinity phosphate transporter PHT1;4 gene promoter of Arabidopsis thaliana in transgenic wheat

• Published in: Biologia plantarum Vol. 61; no. 3; pp. 453 - 462
• Main Authors: Peñaloza, E., Santiago, M., Cabrera, S., Muñoz, G., Corcuera, L. J., Silva, H.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.09.2017; Springer Nature B.V; Institute of Experimental Botany of the Czech Academy of Sciences
• Subjects: Affinity; Assaying; Biomedical and Life Sciences; Genes; gus reporter gene; Hydroponics; Life Sciences; Original Paper; Phosphate; phosphate deficiency; Phosphate transporter; Phosphates; Plant Sciences; Plants (botany); Progeny; Promoters; Reporter gene; Roots; Soils; Staining; Sustainability; Transgenes; Transgenic plants; Triticum aestivum; Wheat; phosphate deficiency; reporter gene
• ISSN: 0006-3134; 1573-8264
• DOI: 10.1007/s10535-016-0672-9

The root specificity and phosphate (Pi) deficiency responsiveness of high-affinity phosphate transporter ( PHT1 ) genes point to their promoters as a sustainable system to drive Pi acquisition-related transgenes in plants. In this study, a 3-kb promoter of the AtPHT1;4 gene from Arabidopsis thaliana fused to the β-glucuronidase ( GUS ) reporter gene was biolistically introduced into wheat ( Triticum aestivum L.) and functionally characterized in transgenic plants grown in hydroponics and in pots with soil under various Pi supply rates. From among 27 T 1 progeny derived from 250 T 0 , four transgenic lines reached T 3 , with two of them showing detectable GUS activity in the roots of T 4 plants. An unusually high number of transgene insertions characterized these transgenic lines, along with an irregular pattern of histochemical GUS staining and weak GUS activity. GUS expression driven by AtPHT1;4 was consistently higher under most assay conditions, as it was unaffected by 0 to 0.5 mM Pi in hydroponically grown plants, as well as by 16 to 20 mg(P) kg -1 (soil) in potted plants. Raising the soil P up to or above 40 mg kg -1 significantly down-regulated the quantity of GUS transcripts. These results show that the responsiveness of the AtPHT1;4 promoter to Pi availability in transgenic wheat was restricted to soil-grown plants, which highlighted the relevance of the substrate and Pi supply rates in assessing molecular responses to Pi deficiency.